[llvm] [TTI][Vectorize] Migrate masked/gather-scatter/strided/expand-compress costing (NFCI) (PR #165532)

[Florian Hahn via llvm-commits]

https://github.com/fhahn commented:

> This approach doesn’t work for getGatherScatterOpCost: ARMTTIImpl::getGatherScatterOpCost walks the use chain of a provided LoadInst/StoreInst, whereas ICA currently expects an IntrinsicInst. Consider introducing getMemIntrinsicInstrCost to cover this scenario..

Thanks for pushing to unify this. I think the description is currently out-of-date with the implementation and would need updating

https://github.com/llvm/llvm-project/pull/165532